Product Queries

queries.rb

# Given these models:
#
# Customer
#   - name: string
#
# Product
#   - price: integer
#
# Order
#   - customer_id: integer
#   - shipping: integer
#   - total: integer
#
# LineItem
#   - order_id: integer
#   - product_id: integer
#   - price: integer
#
# and assume every model as a method called 'sample' which will
# return a random row from the database.
#
#
# Given:
#   the_order = Order.sample
#   the_product = Product.sample
#
# Can you write code to answer each question?

# 1. How many customers do we have?

# 2. What is the most expensive thing we sell?

# 3. What is the subtotal of the_order (the cost all items excluding shipping)?

# 4. On average, how much is spent on a typical order?

# 5. How many different products were purchased in the_order?

# 6. How many times has the_product ever been purchased?

# 7. How many orders contain the_product?

# 8. How many items in the_order cost more than $100?

# 9. How many people bought the_product?

# 10. What's the most popular product we sell?

1. Cusomer.count
2. Product.where( price: Product.maximum('price'))
3. the_order.total - the_order.shipping
4. Order.average(:total)
5. LineItem.where(order_id: the_order.id).count
6. LineItem.where(product_id: the_product.id).count
7. LineItem.where(product_id: the_product.id).pluck(:order_id).uniq.count
8. LineItem.where(order_id: the_order.id).where("price > 100").count